Truth about lenses any lens

[donny1963]

Truth about lenses any lens

Ok i saw this video that Ken put out and he hit the nail on the head about lenses, i always
knew this and i can't agree with more..
Want to know the truth about lenses watch this..


It's like this there is always a sweet spot to where you focus your lens, just like every lens has a Aperture Sweet Spot where it captures it's sharpest..
This is why some times when some one uses a specific lens does portraits and wonders why one picture is not quite as sharp as another,

and many times it's due to where it was very sharp you had your lens at it's sweet spot and the other picture that was not so hot, is because it was NOT at it's sweet spot..

 

[Derrel]

.!!

 

[Jeff15]

There are many experts.....?????>>>>>

 

[petrochemist]

There are many experts.....?????>>>>>

All his videos I've started watching have been so full of BS that I now click away from any links as soon as I recognise him.

Fortunately this time I didn't even have to click Donny's link to know it wasn't worth the effort.

Yes lenses are often optimised for a specific role, and will not be as good when used for situations far from that role - using normal lenses for extreme macro is such an example.
Less extreme cases rarely make any significant difference. Macro lenses can be good for portraiture (if sharp images are wanted), and portrait lenses can work well for landscapes when the focal length fits the desired FOV.

 

[Braineack]

Why can't this guy light his videos worth sh*t?

Why do always post this guy like we care?

Why don't you understand the definition of truth?

 

[Designer]

Who all watched the video?

I did.

 

[Braineack]

I'm sorry

 

[Derrel]

Gasbag or legit source of hot air? Disclaimer :The above photo was made with a lens.

 

[tirediron]

Someone owes me 13:40 of my life back! It's difficult to imagine how evolution was able to cram that much stupid in one head!

 

[Braineack]

I'm still trying to figure out the point of his video.

 

[Designer]

I'm still trying to figure out the point of his video.

His point was that lens manufacturers "stretch" "embellish" (falsify) the usable focal length of zooms for marketing purposes. People then purchase these lenses and find that the image quality suffers at the extreme ends of the zoom range, with distortion, a lack of sharpness, and vignetting.

A similar practice is done with the stated apertures of prime lenses. Manufacturers claim a certain wide aperture, when the lens actually works better at a somewhat reduced aperture. It's not as if you have not heard this before.

The "measure-baters" see the loss of performance in the edges and corners, and heap heavy criticism on the lens because they expected the lens to perform flawlessly at the closest and farthest extent of the zoom range, all the way out to the edges with sharp focus, no distortion, and no vignetting.

So even though lenses usually perform quite well when not pushed to their extremes, the marketing division wins when writing the specifications. Quite simply, they sell more lenses that way. Think that is dishonest? Some people think it is a dishonest way to promote sales.

I think that since we know this, we can usually adjust by not expecting a zoom to be without distortion/vignetting, and a prime lens to be sharper and with better contrast when slightly stopped down.

I understand some people don't like the presenter (for various reasons) but this video had a very simple message that even I could understand.

 

[limr]

I'm still trying to figure out why y'all even bother with these threads.

 

[tirediron]

I'm still trying to figure out why y'all even bother with these threads.

Because my plan was this morning was to sit on the chesterfield and hit myself in the head with a hammer for 15 minutes; I couldn't find my hammer, so this was an effective substitute!

 

[tirediron]

I'm still trying to figure out the point of his video.

His point was that lens manufacturers "stretch" "embellish" (falsify) the usable focal length of zooms for marketing purposes. People then purchase these lenses and find that the image quality suffers at the extreme ends of the zoom range, with distortion, a lack of sharpness, and vignetting.

A similar practice is done with the stated apertures of prime lenses. Manufacturers claim a certain wide aperture, when the lens actually works better at a somewhat reduced aperture. It's not as if you have not heard this before.

The "measure-baters" see the loss of performance in the edges and corners, and heap heavy criticism on the lens because they expected the lens to perform flawlessly at the closest and farthest extent of the zoom range, all the way out to the edges with sharp focus, no distortion, and no vignetting.

So even though lenses usually perform quite well when not pushed to their extremes, the marketing division wins when writing the specifications. Quite simply, they sell more lenses that way. Think that is dishonest? Some people think it is a dishonest way to promote sales.

I think that since we know this, we can usually adjust by not expecting a zoom to be without distortion/vignetting, and a prime lens to be sharper and with better contrast when slightly stopped down.

I understand some people don't like the presenter (for various reasons) but this video had a very simple message that even I could understand.

His point is to attract viewers to increase revenue.

That said, his "message" seemed to be that lens manufacturers are somehow "cheating" buyers, or mis-representing their product. The simple fact is, if you want a lens to work well through a range of X - Y focal length, than you need to build it with a range of X-x - Y+y. If I want my truck to be able to pull a 10,000 pound trailer all day, under all conditions, I need to design it with surplus capacity, so I build it to tow 15,000 pounds. It wouldn't be prudent to do that all the time, but it CAN do it. Just like the 16-35mm lens can extend to focal lengths of 16 and 35mm. Is it perfect there? No, of course not, but it does function. Are manufacturers doing anything sneaky? No. They're simply telling you what the focal length of the lens is.

 

[Braineack]

He also makes fun of pixel peepers who care about corner sharpness at the same time...

He also confuses marketing techniques with physical limitations in optics.